Reactivity of synovial T cells to mycobacterial 65kd heat shock protein (HSP) has been recently found in rheumatoid arthritis (RA) and other inflammatory arthritic conditions. Given the high degree of homology between bacterial HSP's and self HSP's it has been hypothesized that such cells are playing a role in the pathogenesis due to their cross-reactivity with self HSP's. The proposed research will test this hypothesis by studying a panel of mycobacteria-reactive CD4 CD8 gammadelta and CD4+alphabeta T cell clones previously isolated from synovial fluid of a RA patient. The antigenic specificity of these cells will be defined by studying proliferation and cytotoxicity in response to purified mycobacterial 65 kd HSP and recombinant human HSP 60 (the human homologue of the mycobacterial 65kd HSP), and other purified mycobacterial and human HSP's and in response to injured cells. The effector function of these cells will be assessed by studying the lymphokines that these cells can produce upon stimulation with the mycobacterial or self HSP, or with mitogens. The requirement of class II HLA antigens and CD1 for antigen presentation to gammadelta clones will be studied by phenotyping antigen presenting cells, by blocking experiments with monoclonal antibodies, by using sublines and mutants of antigen presenting lines and by using cell lines transfected with class II HLA genes. The HLA restriction of antigen presentation to the CD4+alphabeta cells will be studied using homozygous tissue typing cells and antigen presenting cells from non-DR4 RA patients, to test the shared epitope hypothesis. The requirement of antigen processing for antigen recognition by gammadelta T cells will be studied. The T cell receptor delta cDNA's will be cloned and sequenced using the anchored PCF technique. Finally, frequency of synovial fluid and peripheral blood T cells bearing gammadelta regions used by these gammadelta T cell clones will be studied in patients with RA and controls. These studies offer a direct approach to assess the role of HSP in RA and provide an opportunity to address basic questions regarding the function of a newly described subset of T cells, gammadelta cells, and their possible role in autoimmunity.